Wrapping machine



June I, 1954 BROOK WRAPPING MACHINE 3 Sheets-Sheet 1 Filed April 21,1952 O a. o m x x I U m A o m %0 F 0 L/(\ IWENTO XW Q AWTUENEV June 1,1954 BROOK I 2,679,765 WRAPPING MACHINE Filed April 21, 1952 3Sheets-Sheet 2 INVENT R 87 M s M L. BROOK WRAPPING MACHINE June 1, 19543 SheetsSheet 3 Filed April 21, 1952 Invv'nfiv Xenia/MO 5! w I Plum,qTranuEys Patented June 1, 1954 WRAPPING MACHINE Application April 21,1952, Serial No. 283,333

Claims.

In wrapping machines, it is often desirable to impart oscillating orreciprocating movement to a part (e. g. a lifting plunger) in onedirection through a spring and to return the driven part positively, thespring yielding in the event of an obstacle to movement of the drivenpart and so preventing damage to the mechanism. However, the forceapplied to the spring in the event of stoppage of the driven partincreases the continued movement of the driving member. She spring mustnot therefore be too strong, otherwise the mechanism may be damaged,despite the provision of the spring, in the event of obstruction of thedriven part. On the other hand, the spring must be strong enough toimpart positive movement to the driven part under nor mal conditionswithout bouncing, which is liable to occur at high speeds. It is oftendifficult in practice to reconcile these conflicting requirements.

With a view to avoiding this difficulty the invention provides, in awrapping machine, the combination of a driven member mounted to rockabout an axis, a driven member mounted to rock about the same axis, aspring disposed between the driving and driven members and serving toimpart movement in one direction from the driving to the driven member,the spring being so mounted as to be capable, in the event ofobstruotion to movement of the driven member, of changing its line or"action in the direction to reduce the mechanical advantage which exertson the driven member, and an abutment for positively imparting returnmovement from the driving to the driven member. The spring will, ofcourse, yield in the event oi obstruction of the driven member, andbecome stronger as a result of continued movement of the driving member,but its mechanical advantage will progressively decrease. Consequentlyit is possible to use a spring which is strong enough to resist bouncingwithout risk of damage to the mechanism when the driven member isobstructed, and without imposing undue loading on the parts which impartrocking movement to the driving member.

One specific application or" the invention, which will shortly bedescribed in detail, is to the lifting plunger in a bunch wrappingmachine of the kind described in my copending U. S. application SerialNo. 283,332, but the invention is equally applicable to the liftingplunger of a twist wrapping machine or to other parts of wrappingmachinery, e. g. to a picker for pulling a web of wrapping material intoposition above the lifting plunger or to mechanism for moving a heatsealing member wrapped article.

The above mentioned specific application of the invention will now bedescribed in detail, by Way of example, with reference to theaccompanying drawings, in which:

Fig. 1 is a side elevation of a bunch wrapping machine for wrappingconfectionery,

Fig. 2 is a side elevation, on a larger scale, of the mechanism foractuating the lifting plunger or the machine, and

Fig. 3 is a view similar to Fig. 2 but showing the parts in thepositions which they assume when upward movement of the lifting plungeris obstructed.

The machine shown in Fig. 1 is described in more detail in U. 5.application Serial No. 283,332 and it will be sufficient to explain herethat a web it of wrapping material is fed from a reel H, by a picker notshown, over rollers 52 and i3 and thence over an adjustable feed tablepast a pair of cutting knives. These are periodically actuated, by acam-operated bar 55, to sever a wrapper from the leading edge of theweb. One of the severed wrappers is indicated at it in Fig. 2. A secondreel ill of wrapper is provided for use when the reel i i is exhausted.

The picker is operated by a bell crank 16, which is periodicallyoscillated, by a cam actuated driving lever 1?, to impart reciprocatingmovement to the picker. A link 9 is periodically raised and lowered, bymeans of a lever l8 operated by another cam, to open and close thepicker jaws at the proper tirnes. The lever 13 is coupled by a linkagei9 and a rod 2% to a clamp 2|, which is lowered to clamp the web ofwrapping material while the knives are operating and is moved toinoperative position when the picker jaws close to feed the web ofwrapper forward.

Ihe tablets to be wrapped are fed by hand into recesses 23 in ahorizontal feed disc 2 which is intermittently rotated to bring thetablets in succession into position above a lifting plunger 25. This isperiodically lii ted, as later described, to lift a tablet, and awrapper it which has been fed into position above it, through an annularbrush contained in a member 2? and into a pair of grippers 28 on acarrier head 29, a cam-operated top plunger 3% having previouslydescended through the brush to press the wrapper against the tabletduring its transit through the brush. She carrier head 23 isintermittently rotated and the wrapping of the tablets is completed onthe carrier head as described in U. S. application Serial No. 283,332.

The lifting plunger 25 is mounted, as shown in,

into contact with a Fig. 2, on the upper end of a bar 26, supported bytwo pivoted links, the upper link 3| being periodically rocked by a cam33 to raise and lower the plunger and the lower link 32 serving tocontrol the plunger so that it executes an approximately straight linemovement. It is necessary that the plunger should be spring driven inthe upwarddirection so that it may come to rest if it meets anobstruction, e. g. if a tablet should fall off the plunger and foul somepart of the machine. A positive return movement is necessary to makesure that the plunger is fully withdrawn below the feed disc before thelatter starts to rotate.

The upper link 3| is pivoted on a rocking shaft 34, to which is fixed anarm 35 carrying a follower 36 which coacts with the cam 33 to rock theshaft 34. Fixed to the shaft 34 is a bell crank 31 and a compressionspring 38 is mounted between the lower arm of the bell crank 37 and theundersurface of the link 3|. An adjustable screw 39, depending from theupper arm of the bell crank, bears against the upper surface of the link3| and serves to impart positive return movement to the plunger 25.Adjustment of the screw 39 also serves to effect vertical adjustment ofthe plunger 25 in relation to the feed disc 24.

The spring 38 surrounds a rod 46 and is mounted in compression betweentrunnion blocks 4|, 42 on the rod 40. The lower trunnion block 42 isfixed to the rod 46 and its trunnions 43 engage slots 44 in the lowerarm of the bell crank 31. The upper trunnion block 4| is slidable on therod 43 and its trunnions 45 engage slots 66 (see Fig. 3) in the loweredge of the link 3|. The upper trunnions 45 are nearer the centre of therocking shaft than the lower trunnions 43.

If the plunger 25 meets an obstruction, the link 3| will cease to move.Continued upward movement of the lower arm of the bell crank 3'! willthen, as shown in Fig. 3, cause the rod 40 to pivot about the arrestedupper trunnions 45, and as the lower trunnions 63 continue to move in anare about the centre of the rocking shaft 34, the line of action of thespring 38 will be changed, becoming progressively more nearly radial tothe rocking shaft 34. Despite, therefore, that the spring 38 becomesstronger as it is compressed, its mechanical advantage becomesprogressively smaller, so avoiding risk of damage to the mechanism andreducing the loading on the cam 33 and bell crank 31.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a wrapping machine, the combination of a pivotally mounted drivingmember comprising an arm projecting from its pivotal axis, means forperiodically rocking said driving member to perform a forward strokeaway from a home position followed by a return stroke, a driven membermounted to pivot on the same axis as said driving member and comprisingan arm projecting from said pivotal axis, said driven member beingnormally movable without obstruction about said pivotal axis through thesame are as said driving member, a spring disposed between said arms forimparting movement from the driving member to the driven member duringthe forward stroke of said driving member, said spring being disposed sothat during the initial stage of its forward stroke the portion of thearm on said driving member adjoining said spring moves substantially inthe axial direction of said spring, connecting means between said springandsaid arms which permit, in the event of obstruction to movement ofthe driven member during the forward stroke of the driving member,movement of the spring from its initial position in relation to saidarms in the direction to bring its line of action progressively nearer aposition radial to said pivotal axis, and an abutment for positivelyimparting movement from the driving member to the driven member on thereturn stroke of said driving member.

2. In a wrapping machine, the combination of a pivotally mounted bellcrank, a cam, means actuated by said cam for periodically rocking saidbell crank to perform a forward stroke away from a home positionfollowed by a return stroke, a driven member mounted to pivot on thesame axis as said bell crank, said driven member being normally movablewithout obstruction about said pivotal axis through the same arc as saidbell crank, a compression spring disposed between one arm of said bellcrank and said driven member for imparting movement from the bell crankto the driven member during the forward stroke of the bell crank, saidspring being disposed so that during the initial stage of the forwardstroke of said bell crank the portion of said arm adjoining said springmoves substantially in the axial direction of said spring, connectingmeans between the spring, said arm and said driven member which permit,in the event of obstruction to movement of said driven member on theforward stroke of the bell crank, movement of said spring from itsinitial position in relation to said arm and driven member in thedirection to bring its line of action progressively nearer a positionradial to said pivotal axis, and an abutment on the other arm of saidbell crank for positively imparting movement from the bell crank to thedriven member on the return stroke of said bell crank.

3. In a wrapping machine, the combination of a pivotally mounted bellcrank, a cam, means actuated by said cam for periodically rocking saidbell crank to perform a forward stroke away from a home positionfollowed by a return stroke, a driven member mounted to pivot on thesame axis as said bell crank, said driven member being normally movablewithout obstruction about said pivotal axis through the same arc as saidbell crank, a compression spring disposed between one arm of said bellcrank and said driven member for imparting movement from the bell crankto the driven member during the forward stroke of the bell crank, saidspring being disposed so that during the initial stage of the forwardstroke of said bell crank the portion of said arm adjoining said springmoves substantially in the axial direction of said spring, a roddisposed inside said spring, a first trunnion block fixed on one end ofsaid rod and carrying trunnions which are accommodated in slots in saidarm, a second trunnion block mounted to slide on the other end of saidrod and carrying trumiions which are accommodated in slots in saiddriven member, said first trunnion block being located further from saidpivotal axis than said second trunnion block, and an abutment on theother arm of said bell crank for positively imparting movement from thebell crank to .the driven member on the return stroke of said bellcrank.

4. In a wrapping machine, the combination of a pivotally mounted bellcrank, a cam, means actuated by said cam for periodically rocking saidbell crank to perform a forward stroke away from a home positionfollowed by a return stroke, a driven member mounted to pivot on thesame axis as said bell crank, said driven member being normally movablewithout obstruction about said pivotal axis through the same are as saidbell crank, a compression spring disposed between one arm of said bellcrank and said driven member for imparting movement from th bell crankto the driven member during the forward stroke of the bell crank, saidspring being disposed so that during the initial stage of the forwardstroke of said bell crank the portion of said arm adjoining said springmoves substantially in the axial direction of said spring, connectingmeans between the spring, said arm and said driven member which permit,in the event of obstruction to movement of said driven member on theforward stroke of the bell crank, movement of said spring from itsinitial position in relation to said arm and driven member in thedirection to bring its line of action progressively nearer a positionradial to said pivotal axis, and an adjustable screw on the other arm ofsaid bell crank, said screw constituting an abutment for positivelyimparting movement from the bell crank to the driven member on thereturn stroke of said bell crank.

5. In a wrapping machine, the combination with a lifting plunger forlifting articles in succession into a wrapping mechanism of a pivotallymounted driving member comprising an arm projecting from its pivotalaxis, a cam arranged to periodically rock said driving member to performa forward stroke away from a home position followed by a return stroke,a driven member mounted to pivot on the same axis as said driving memberand normally free to move without obstruction about said pivotal axisthrough the same are as said driving member, a linkage connecting saiddriven member to said lifting plunger, and arranged to raise and lowersaid lifting plunger in response to rocking movement of said drivenmember, said riven member comprising an arm projecting from said pivotalaxis, a spring disposed between said arms for imparting movement fromthe driving member to the driven member during the forward stroke ofsaid driving member, said spring being disposed so that during theinitial stage of its forward stroke the portion of the arm on saiddriving member adjoining said spring moves substantially in the axialdirection of said spring, connecting means between said spring and saidarms which permit, in the event of obstruction to movement of the drivenmember during the forward stroke of the driving member, movement of thespring from its initial position in relation to said arms in thedirection to bring its line of action progressively nearer a positionradial to said pivotal axis, and an abutment for positively impartingmovement from the driving member to the driven member on the returnstroke of said driving member.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,569,672 Peabody Jan. 12, 1926 1,733,936 Boughton Oct. 29,1929 1,833,229 Bent Oct. 18, 1932

